A contractor undertakes to dig a canal 10 km long in 180 days and empl...
In 60 days 40 men completed 2.5 km of the canal.
Let x number of men be required to complete 10 - 2.5 = 7.5 km of the canal in 180 - 60 = 120 days.
M1 xD1 x W2 = M2 x D2 x W1
60 x 40 x 7.5 = x x 120 x 2.5
x = 60 men
So the contractor requires 60 - 40 = 20 more men to complete the work on the scheduled time.
Hence, option 2.
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A contractor undertakes to dig a canal 10 km long in 180 days and empl...
Given information:
- Length of the canal to be dug: 10 km
- Time allocated for the work: 180 days
- Number of men employed: 40
- After 60 days, only 2.5 km of the canal has been completed
To find:
- How many more men does the contractor need to employ in order to complete the work on time?
Calculation:
1. First, we need to find the rate at which work is being done by the current number of men.
- In 60 days, the work completed is 2.5 km.
- Therefore, the rate of work is 2.5 km/60 days = 1/24 km per day.
2. Now, let's find the total work remaining to be done.
- Total length of the canal to be dug = 10 km
- Work completed so far = 2.5 km
- Therefore, work remaining = 10 km - 2.5 km = 7.5 km.
3. Next, we calculate the number of days required to complete the remaining work at the current rate of work.
- Rate of work = 1/24 km per day
- Work remaining = 7.5 km
- Number of days required = (7.5 km) / (1/24 km per day) = 7.5 x 24 = 180 days
Analysis:
- The calculation shows that at the current rate of work, the contractor will need the full 180 days to complete the remaining 7.5 km of the canal.
To complete the work on time, the contractor needs to increase the number of men. Let's calculate how many more men are required.
4. We know that the total work remaining is 7.5 km, and the contractor wants to complete it in the remaining 120 days (180 days - 60 days).
- Work remaining = 7.5 km
- Time remaining = 120 days
- Rate of work required = Work remaining / Time remaining = 7.5 km / 120 days = 1/16 km per day
5. Now, let's calculate the number of men required to achieve the desired rate of work.
- Rate of work per man = 1/24 km per day
- Desired rate of work = 1/16 km per day
- Number of men required = (Desired rate of work) / (Rate of work per man) = (1/16) / (1/24) = 24/16 = 3/2
Therefore, the contractor needs to increase the number of men by 3/2 or 1.5.
Final Answer:
- The contractor needs to increase the number of men by 1.5, which is equivalent to 1.5 x 40 = 60.
- Therefore, the contractor needs to increase the number of men by 60 to complete the work on time.
The correct answer is option (B) 20.
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